Harold Hall

This is a simple assembly, Photograph 3, with only a few areas needing special attention.

Posts (13 and 14)

The first essential feature is that, whilst their length is not critical, all four posts should be the same, say within +/- 0.03 mm. To do this, set up a backstop in your lathe bore and drill, tap and face the end of the first post. Reverse the post in the chuck ensuring that it is now firmly against the backstop. Also fit a saddle stop and with the saddle firmly against this again drill, tap, and very lightly face the end of the bar using the top slide to establish the part's length, DO NOT now move either the saddle or the top slide.

Metalworking

Workshop Projects

Main Frame Assembly.

I find it difficult not to instinctively adjust the top slide so, if like me, place a flag of masking tap on its handle as a reminder not to do so.

Fit the second post and with the saddle away from the saddle stop, face, drill and tap the first end, then, with the part reversed in the chuck and the saddle now against the saddle stop, the second end is faced, drilled and tapped ensuring, as a result, that it is the same length as the first. Photograph 4 shows that I used my three way tailstock turret to avoid continually changing centre drill, drill and tap and also that I used the auto feed mechanism from my controlled feed tapping stand. This makes tapping, even in the lathe, delightfully simple. Repeat for the remaining two posts.

Remove the post and measure its length to determine how much more requires to be removed, return to the chuck, again against the backstop, and using the top slide set on the amount to be removed, finally face to length. It is essential that the top slide is now left in that position for the remaining three posts.